I took an action item to write another formulation of the issue for the
WS-Addressing wg. Sorry my absence got in the way, but here is my
writeup.
* Title: The [reply endpoint] and [fault endpoint] MAPs with values
other than anonymous endpoints are not usable in conjunction with known
SOAP/HTTP bindings and WSDL MEPs.
* Description: One of the major utilities of WS-Addressing is the
ability to specify the redirection of responses and faults in a message
exchange. Current WS-Addressing specification defines two MAPs for these
purposes. However, their utility when used in conjunction with known
SOAP/HTTP bindings are limited since only anonymous endpoints can be
specified as their value. The behavior of WSDL MEPs and support from
underlying bindings when other values are engaged is currently not
known. For example, SOAP bindings over HTTP [1], [2] do not specify a
means for using a separate connection for sending responses. This limits
the utility of current SOAP 1.1 and SOAP 1.2 bindings in conjunction
with WSDL MEPs that specify responses or faults to be sent as a result
of receiving (or sending) a message, such as WSDL 1.1 request-response,
WSDL 2.0 in-out, in-optional-out, robust-in MEPs, etc. in an
asynchronous fashion.
In addition to this problem, the current interaction of abstraction
layers with WSDL MEPs, SOAP MEPs, and SOAP bindings require definition
of additional SOAP MEPs in order to enable WSDL MEPs for which there is
no corresponding SOAP MEP. Although this appears to be a related, but a
separate problem on the surface, the usage of WS-Addressing in
conjunction with SOAP MEP(s) that correspond to a WSDL MEP affects the
WSDL binding specification and further composition of WSDL MEPs that may
use these MAPs in a coordinated fashion (i.e. two one-way MEPs). The
abstraction layer interaction problems are illustrated in detail in [3].
The Async Task Force has established several use cases [4] that
illustrate how asynchronous usage of message exchanges is needed.
Further, test case scenerios that were submitted to the wg [5] would
require the WS-Addressing wg to establish well known semantics with
target SOAP bindings and WSDL MEPs that allow using these two MAPs in an
interoperable fashion.
* Justification:
WS-Addressing charter clearly indicates that the usage of WSDL MEPs in
an asynchronous fashion is in within the scope of this working group. In
addition, test suite will need to define a concrete semantics for using
these two MAPs in conjunction with the WSDL binding document for
ensuring interoperability.
[1] http://www.w3.org/TR/2000/NOTE-SOAP-20000508/
[2] http://www.w3.org/TR/2003/REC-soap12-part2-20030624/
[3]
http://www.pacificspirit.com/blog/2005/04/05/underlying_protocol_is_a_co
mpletely_leaky_abstraction
[4] http://lists.w3.org/Archives/Public/public-ws-async-tf/2005Feb/
[5]
http://lists.w3.org/Archives/Public/public-ws-addressing/2005Mar/0209.ht
ml